Variation in plant belowground resource allocation across heterogeneous landscapes: implications for post-fire...

Area of Science:

• Ecology
• Plant Physiology
• Disturbance Ecology

Background:

• Resource availability influences plant biomass allocation strategies.
• Plant responses to disturbance, like fire, are linked to resource availability.
• Fire regimes vary across landscapes and correlate with resource availability.

Purpose of the Study:

• To test the hypothesis that plants in nutrient and water-limited microsites allocate more biomass belowground.
• To investigate if this increased belowground allocation enhances post-fire resprouting ability.
• To compare biomass and root starch allocation across different topographic and resource gradients.

Main Methods:

• Study sites selected across three contrasting topographies (gullies, midslopes, ridges) in Jalisco, Mexico.
• Measured soil nutrient, water content, and light availability at each site.
• Sampled biomass and root starch allocation in three common post-fire resprouting shrubs.

Main Results:

• Ridges exhibited higher solar radiation and lower soil nutrients and water.
• Plants in ridges and midslopes showed significantly higher root-to-shoot (R/S) ratios.
• Greater fine root biomass and higher root starch content were observed in plants from ridges and midslopes compared to gullies.

Conclusions:

• Plants in resource-limited, open canopy sites allocate more biomass belowground.
• This belowground investment may enhance resprouting capacity after disturbances like fire.
• Plants in mesic, fertile forest sites may be more susceptible to disturbances such as wildfires.